Fogging, icing and misting may be experienced on vehicle glass under certain environmental conditions. For example, formation of ice on the exterior surface of vehicle glass may occur when ambient temperature is below freezing. Or, condensation may form on the inside surface of the glass when there is high relative humidity inside the vehicle and where the glass is cool due to a lower temperature outside the vehicle. Condensation may also form on the outside of the glass if cold air is blown onto the inside of the glass in an attempt to remediate a misting condition.
A vehicle may include a heating, ventilation and air-conditioning (HVAC) system to allow a user to set a desired air temperature within the passenger cabin of the vehicle. For example, the HVAC system may provide controls that allow a driver to select a temperature or heat setting through a climate control head unit. A controller of the HVAC system may then operate the HVAC system to achieve the desired temperature or setting. The controller may further facilitate the user configuration of additional settings, such as fan speed, air conditioning (A/C) compressor operation, recirculation and defrost. Based on the received settings, the HVAC system may control a blower and the positioning of various air doors to control movement of recirculated and fresh air through one or more of an evaporator core and a heater core.
An electronic automatic temperature control (EATC) module may be included in an HVAC system to adjust the level of heating and cooling in the vehicle based on status signals received from sensors and controllers located throughout the vehicle. Accordingly, certain EATC modules may direct the HVAC system to address fogging, icing and misting conditions on the vehicle glass. However, existing EATC modules and manual user inputs may have issues with the efficiency or effectiveness in keeping the windshield and other vehicle glass sufficiently clear.